I've
been told that there are grades of zinc anodes. Which one should I use
for the best protection?R.G., via e-mail

For
best protection against galvanic corrosion, use only zincs intended specifically
for that purpose. Look for Mil Spec--a military specification standard--Mil-A-1800J
stamped somewhere on the zinc. The final letter designation J is the lowest
letter permitted for galvanic corrosion protection and indicates that
the zinc meets the technical description. When you purchase a new zinc,
make sure it has a J or higher letter. If not, or if no specification
stamp is present, do not buy it.

Why
must the charging voltage of a battery charger be more than 13 volts?
A.S., via e-mail

If the
battery charger and the battery have the same voltage, there will be no
flow of current to the battery. (In fact, if the voltage of the battery
is higher than that of the charger, the battery will discharge.) Most
chargers are rated at 13.8 volts, a few at 14 or higher. The greater the
difference between the voltages, the greater the current flow, and as
battery voltage increases, the rate of charging will slow. Directly after
charging, battery voltage may read as high as 14, but this "surface
charge" will quickly drop as soon as a load is put on. If no load
is present, the voltage will slowly decrease on its own.

I'm
putting down new interior decking, and part of the galley sole is covered
with vinyl tiles. Prying them up is quite difficult. Any suggestions?P.G., via e-mail

Set
a steam iron to a medium setting and lay a piece of cloth over the tile.
Run the iron back and forth across the cloth. As the vinyl and the adhesive
heat up, you should be able to pry the tiles up with a putty knife. If
the tiles still prove to be stubborn, increase the heat. If a steam iron
is inconvenient, use a heat gun.

After
you remove the tiles, you may find some surplus adhesive on the sole.
Apply hot water to soften it sufficiently so you can scrape it up, or
mix one part vinegar to three parts of water and let the liquid sit on
the adhesive for at least 30 minutes. This should soften up the glue enough
that you can remove it with a wide putty knife. Clean the knife off immediately
to prevent the glue from building up.

If there
is still some adhesive residue left that you need to remove, try grinding
it smooth, but make sure to use safety goggles.